The Bruins are knee-deep in their first Stanley Cup Final for the first time in 21 years and Boston’s active goalie has emerged as the team’s ultimate grinder.

Thomas has been the goaltender in every second of every one of the Bruins 20 playoff games. He had allowed only one goal in six periods of hockey prior to last night’s 3-2 loss to the Canucks in overtime.

He stands tall (actually, only 5 feet 11 inches) as the Bruins’ best hope to bring a Stanley Cup to Boston for the first time since 1972, when Gerry Cheevers was the Hub of Hockey’s popular goalie, also wearing No. 30.

Thomas makes a pile of dough these days and may win his second Vezina Trophy, but everything else about him says, “regular guy.’’

Radio sports talker Gerry Callahan correctly noted that Thomas looks a lot like Zach Galifianakis of “The Hangover’’ fame. Indeed. The playoff beard only adds to the resemblance. Thomas looks like a guy who’d be watching the game at The Four’s on Canal Street if he wasn’t tending the net. He won the Seventh Player Award in 2006 and 2007. It’s an award, voted by the fans, not normally bestowed on the famous, the wealthy, and the non-checking.

But fans know Thomas got here the hard way.

Start with his hometown of Flint, Mich. It’s never been described as “tony’’ Flint. More like hardscrabble Flint. Thomas’s dad, Tim Sr., was a car salesman in Flint when the American auto industry started to crumble in the 1980s. When he was a kid, Thomas’s parents hawked their $1,500 wedding bands for $200 so Tim could play in a hockey tournament in Canada. He didn’t learn about that sacrifice until he was on scholarship at the University of Vermont.

Thomas was drafted in the ninth round in 1994 and his path to the NHL included stints with the Birmingham Bulls, Houston Aeros, IFK Helsinki, Hamilton Bulldogs, Detroit Vipers, AIK Solna (Sweden), Karpat (Finland), and Providence (AHL). He spent nine years in the minors and didn’t make it full time in the NHL until he was 31.

Thomas has represented the United States in seven international competitions, including the 2010 Olympics, when he won a silver medal right here at Rogers Arena, as backup to Buffalo’s Ryan Miller (among those who’ve participated in these playoffs, Thomas is the only American-born Bruin).

It’s hard to remember now that Tuukka Rask was the flavor of the month in the Bruins’ goal last spring when the team collapsed against Philadelphia. It’s been all Thomas this season and longtime Bruins boss Harry Sinden says Thomas is Boston’s best goalie since the legendary Cheevers.

Vancouver’s Roberto Luongo is a classic butterfly-style goalie. With an assist from Patrice Bergeron, Thomas describes his method as “battlefly.’’

Thomas’s unorthodox style is getting a lot of attention in these playoffs. His diving, stick save of a Steve Downie shot near the end of the Bruins’ Game 5 win against Tampa Bay is already part of Boston sports lore. Thomas’s acrobatics got the attention of Luongo, who said he likes to face away from the goal, while Thomas seems to make many of his saves while looking into the net.

Thomas’s tendency to roam irked Vancouver coach Alain Vigneault, who thought Canucks winger Alex “Jaws’’ Burrows picked up a tripping penalty because Thomas was out of the goaltender’s area. Last night, Burrows got revenge, faking a slap shot that pulled Thomas out of his net, then swinging around the net for a wraparound goal 11 seconds into overtime.

“Ninety percent of his saves are where he’s outside the blue paint,’’ Vigneault said before last night’s game. “A lot of times he does initiate contact. That’s the way he plays. Roberto played sort of the same way last year. We got in trouble because of that. We fixed that this year. We said that we were going to look to get a little bit of clarification on certain situations.’’

“Well, that’s his style,’’ countered Bruins coach Claude Julien. “I mean, if he gets a chance to challenge, he challenges. The rule is pretty clear. You’re entitled to your ice.’’

“Basically I have the right to go anywhere there’s open ice,’’ said Thomas. “If I’m set, I have a right to that ice. If I’m out of the paint and I’m set, I also have the right to get right-of-way to get back to the crease.

“I just play my game. It’s not always in the blue. You’ve got to do what you got to do.’’

It’s working. Before last night, Thomas was 3-1 in his last four games against Vancouver, allowing only two goals.

Our everyman goalie will be back between the pipes when the Stanley Cup Final returns to Causeway Street tomorrow night for Game 3. The last line of defense is the Bruins’ best hope to bring the Cup back to Boston.